xenharmonic (microtonal wiki)

In 12EDO, virtually all the catchy/easy chord progressions have been taken. Want some possibilities for new ones? You can't have beautiful/pure 6:7:8, 5:7:9, 7:9:11, 10:11:12...7 and 11-limit chords on your 12EDO keyboard because such chords don't exist in 12EDO. In 12EDO you are stuck with run-of-the-mill 5-limit chords such as major (4:5:6) and minor (10:12:15)...get unstuck with new temperaments in Xenharmony.
At least with JI, there are ways you can go about it where the math or theory doesn't have to be any harder than 12EDO -> http://xenharmonic.wikispaces.com/Mike+Sheiman%27s+Very+Easy+Scale+Building+From+The+Harmonic+Series+Page
If you are into deep mathematical theory...the possibilities for optimization of scales for variety are virtually endless.
If you use electronic instruments that support SCALA files, such as cheap to free VSTi's, you can start composing Xenharmonic music often without spending a dime (list needed).
You know how musicians (cluelessly) warn you about Xenharmony being necessarily dissonant? It's a load of bull ->http://www.cdbaby.com/cd/marcussatellite2 (done in a CPS scale: Hexanies)
http://www.youtube.com/watch?v=BhZpvGSPx6w (done in Just Intonation)